Formaldehyde is a common disinfecting agent in dialyzer membrane reuse procedures. Since formaldehyde is carcinogenic, toxic and malodorous, any safe, cost-effective alternative would be a marketable an medical success. The long-term objective of this proposal is to benefit patient care, employee safety, and cost effectiveness by establishing an economically competitive, non-toxic, market alternative to formaldehyde. The short-term objective is to test the effectiveness of a new cost- effective cold disinfectant technology for dialysis membranes following human use. A secondary objective is to evaluate the effect of this disinfecting process on maintaining fiber bundle volume (FBV). A clinically relevant phase I study evaluating the effect of the cold disinfecting agent on dialyzer membranes will be performed. Biocidal effectiveness will be determined by culturing the dialyzer membranes following a typical 72-hour storage. A second in vitro protocol to evaluate FBV will also be done using dialysis membranes and plasma. The FBV data will be compared to previously obtained data from our unit as well as published observations on maintaining FBV. These protocols should provide relevant and sufficient data to thoroughly evaluate this cold sterilant and, if successful, provide sufficient preliminary work to substantiate a phase II study.